﻿using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Web.Script.Serialization;

namespace SysCommon
{
    public static class Converts
    {
        /// <summary>
        /// js 序列化器
        /// </summary>
        static JavaScriptSerializer jss = new JavaScriptSerializer();

        /// <summary>
        /// 将 对象 转成 json格式字符串
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static string ObjectToJson(object obj)
        {
            //把集合 转成 json 数组格式字符串
            return jss.Serialize(obj);
        }

        #region 2.0 实体转换 +static K CopyModel<T, K>(this T t)where T : class ,new() where K : class ,new()
        /// <summary>
        /// 2.0 实体转换
        /// </summary>
        /// <typeparam name="T">待转实体</typeparam>
        /// <typeparam name="K">转成实体</typeparam>
        /// <param name="t">扩展实体名</param>
        /// <returns>新实体</returns>
        public static K CopyModel<T, K>(this T t)
            where T : class ,new()
            where K : class ,new()
        {
            Type typeT = new T().GetType();
            PropertyInfo[] pt = typeT.GetProperties();
            Dictionary<object, object> dict = new Dictionary<object, object>();

            foreach (var item in pt)
            {
                object pvalue = null;// item.GetValue(t);
                dict.Add(item.Name, pvalue);
            }

            Type typeK = new K().GetType();
            PropertyInfo[] pk = typeK.GetProperties();
            K k = new K();
            foreach (var item in pk)
            {
                if (dict.Keys.Contains(item.Name))
                {
                    //item.SetValue(k, dict[item.Name]);
                }
            }
            return k;
        }
        #endregion

        #region 2.1 集合实体转换 +static List<K> CopyModel<T, K>(this List<T> tList)
        /// <summary>
        /// 2.1 集合实体转换
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <typeparam name="K"></typeparam>
        /// <param name="tList"></param>
        /// <returns></returns>
        public static List<K> CopyModel<T, K>(this List<T> tList)
            where T : class ,new()
            where K : class ,new()
        {
            List<K> listK = new List<K>();
            foreach (T list in tList)
            {
                listK.Add(Converts.CopyModel<T, K>(list));
            }
            return listK;
        }
        #endregion

        /// <summary>
        /// 实体转Json
        /// </summary>
        /// <param name="obj">要转换的实体对象</param>
        /// <returns></returns>
        public static string EntityToJson(object obj)
        {
            StringBuilder jsonStr = new StringBuilder();
            PropertyInfo[] pInfos = obj.GetType().GetProperties();
            string pValue = string.Empty;
            jsonStr.Append("{");
            foreach (PropertyInfo p in pInfos)
            {
                if (!(p.GetValue(obj, null) == null))
                {
                    //转义掉Json格式特殊字符 ‘\’,‘"’
                    pValue = p.GetValue(obj, null).ToString().Replace("\\", "\\\\").Replace("\"", "\\\"");
                }
                else
                {
                    pValue = string.Empty;
                }
                jsonStr.Append(string.Format("\"{0}\":\"{1}\",", p.Name, pValue));

            }
            jsonStr.Remove(jsonStr.Length - 1, 1);
            jsonStr.Append("}");
            return jsonStr.ToString();
        }

        /// <summary>
        /// 转化一个DataTable
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="list"></param>
        /// <returns></returns>
        public static DataTable ToDataTable<T>(this IEnumerable<T> list)
        {
            //创建属性的集合
            List<PropertyInfo> pList = new List<PropertyInfo>();
            //获得反射的入口
            Type type = typeof(T);
            DataTable dt = new DataTable();
            //把所有的public属性加入到集合 并添加DataTable的列
            Array.ForEach<PropertyInfo>(type.GetProperties(), p =>
            {
                pList.Add(p);
                dt.Columns.Add(p.Name, p.PropertyType);
            });
            foreach (var item in list)
            {
                //创建一个DataRow实例
                DataRow row = dt.NewRow();
                //给row 赋值
                pList.ForEach(p => row[p.Name] = p.GetValue(item, null));
                //加入到DataTable
                dt.Rows.Add(row);
            }
            return dt;
        }

        /// <summary>
        /// DataTable 转换为List 集合
        /// </summary>
        /// <typeparam name="TResult">类型</typeparam>
        /// <param name="dt">DataTable</param>
        /// <returns></returns>
        public static List<T> ToList<T>(this DataTable dt) where T : class, new()
        {
            //创建一个属性的列表
            List<PropertyInfo> prlist = new List<PropertyInfo>();
            //获取TResult的类型实例  反射的入口
            Type t = typeof(T);
            //获得TResult 的所有的Public 属性 并找出TResult属性和DataTable的列名称相同的属性(PropertyInfo) 并加入到属性列表 
            Array.ForEach<PropertyInfo>(t.GetProperties(), p =>
            {
                if (dt.Columns.IndexOf(p.Name) != -1)
                    prlist.Add(p);
            });
            //创建返回的集合
            List<T> oblist = new List<T>();

            foreach (DataRow row in dt.Rows)
            {
                //创建TResult的实例
                T ob = new T();
                //找到对应的数据  并赋值
                prlist.ForEach(p =>
                {
                    if (row[p.Name] != DBNull.Value)
                        p.SetValue(ob, row[p.Name], null);
                });
                //放入到返回的集合中.
                oblist.Add(ob);
            }
            return oblist;
        }

        /// <summary>
        /// 将集合类转换成DataTable
        /// </summary>
        /// <param name="list">集合</param>
        /// <returns></returns>
        public static DataTable ToDataTableTow(IList list)
        {
            DataTable result = new DataTable();
            if (list.Count > 0)
            {
                PropertyInfo[] propertys = list[0].GetType().GetProperties();
                foreach (PropertyInfo pi in propertys)
                {
                    result.Columns.Add(pi.Name, pi.PropertyType);
                }

                for (int i = 0; i < list.Count; i++)
                {
                    ArrayList tempList = new ArrayList();
                    foreach (PropertyInfo pi in propertys)
                    {
                        object obj = pi.GetValue(list[i], null);
                        tempList.Add(obj);
                    }
                    object[] array = tempList.ToArray();
                    result.LoadDataRow(array, true);
                }
            }
            return result;
        }

        
        /// <summary>
        /// 将泛型集合类转换成DataTable
        /// </summary>
        /// <typeparam name="T">集合项类型</typeparam>
        /// <param name="list">集合</param>
        /// <returns>数据集(表)</returns>
        public static DataTable ToDataTable<T>(IList<T> list)
        {
            return ToDataTable<T>(list, null);
        }

        /// <summary>
        /// 将泛型集合类转换成DataTable
        /// </summary>
        /// <typeparam name="T">集合项类型</typeparam>
        /// <param name="list">集合</param>
        /// <param name="propertyName">需要返回的列的列名</param>
        /// <returns>数据集(表)</returns>
        public static DataTable ToDataTable<T>(IList<T> list, params string[] propertyName)
        {
            List<string> propertyNameList = new List<string>();
            if (propertyName != null)
                propertyNameList.AddRange(propertyName);

            DataTable result = new DataTable();
            if (list.Count > 0)
            {
                PropertyInfo[] propertys = list[0].GetType().GetProperties();
                foreach (PropertyInfo pi in propertys)
                {
                    if (propertyNameList.Count == 0)
                    {
                        result.Columns.Add(pi.Name, pi.PropertyType);
                    }
                    else
                    {
                        if (propertyNameList.Contains(pi.Name))
                            result.Columns.Add(pi.Name, pi.PropertyType);
                    }
                }

                for (int i = 0; i < list.Count; i++)
                {
                    ArrayList tempList = new ArrayList();
                    foreach (PropertyInfo pi in propertys)
                    {
                        if (propertyNameList.Count == 0)
                        {
                            object obj = pi.GetValue(list[i], null);
                            tempList.Add(obj);
                        }
                        else
                        {
                            if (propertyNameList.Contains(pi.Name))
                            {
                                object obj = pi.GetValue(list[i], null);
                                tempList.Add(obj);
                            }
                        }
                    }
                    object[] array = tempList.ToArray();
                    result.LoadDataRow(array, true);
                }
            }
            return result;
        }
         
    }
}

